Electrospinning of PVA-carboxymethyl cellulose nanofibers for flufenamic acid drug delivery.

A prominent medical application of nanotechnology is represented in drug delivery. In this work, carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) were used for producing CMC/PVA aqueous-based nanofibers loaded with flufenamic acid (FFA) as a drug containing amine groups. The CMC/PVA solutions with 90/10, 80/20, 70/30, 60/40 and 50/50 ratios were considered for electrospinning. Two integration methods were studied for loading FFA on the nanofibers during the electrospinning process. The characterization techniques of SEM, AFM, fluorescence microscopy and FT-IR spectroscopy were used to study the produced nanofibers, indicating a uniform distribution of FFA throughout the samples. The resulting nanofibers were formed in a diameter range of 176-285 nm and exhibited a 5 h degradation time in the PBS buffer solution. A standard diagram of drug loading was obtained for the samples. The drug release pattern was examined using a dialysis tube method. UV-visible spectroscopy revealed a time-dependent drug release behavior in CMC/PVA/FFA nanofibers where a sharp release occurred over the first 20 min. However, a prolonged release time of 10 h was achieved using a cross-linker (EDC).

Electrospinning of Cross-Linked Magnetic Chitosan Nanofibers for Protein Release.

A poly(vinylalcohol) (PVA) electrospun/magnetic/chitosan nanocomposite fibrous cross-linked network was fabricated using in situ cross-linking electrospinning technique and used for bovine serum albumin (BSA) loading and release applications. Sodium tripolyphosphate (TPP) and glutaraldehyde (GA) were used as cross-linkers which modified magnetic-Fe3O4 chitosan as Fe3O4/CS/TPP and Fe3O4/CS/GA, respectively. BSA was used as a model protein drugs which was encapsulated to form Fe3O4/CS/TPP/BSA and Fe3O4/CS/GA/BSA nanoparticles. The composites were electrospun with PVA to form nanofibers. Nanofibers were characterized by field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). The characterization results suggest that Fe3O4 nanoparticles with average size of 45 nm were successfully bound on the surface of chitosan. The cross-linked nanofibers were found to contain uniformly dispersed Fe3O4 nanoparticles. The size and morphology of the nanofibers network was controlled by varying the cross-linker type. FTIR data show that these two polymers have intermolecular interactions. The sample with TPP cross-linker showed an enhancement of the controlled release properties of BSA during 30-h experimental investigation. Graphical Abstract ᅟ.

Aspheric profile versus wavefront-guided ablation photorefractive keratectomy for the correction of myopia using the Allegretto Eye Q.

PURPOSE: To compare the results of photorefractive keratectomy (PRK) with Q-factor customized aspheric ablation and wavefront-guided customized ablation for correction of myopia compound with astigmatism. METHODS: Fifty-six patients were enrolled in this prospective controlled study. In each patient, one eye was randomly assigned for treatment with the Q-factor customized PRK (custom-Q study group) and the other eye treated with wavefront-guided customized PRK. Preoperative and 3-month postoperative manifest refraction, contrast sensitivity, visual acuity, aberrometry, and asphericity of the cornea were compared between the two groups. All eyes were treated with the Wavelight Eye-Q 400 Hz excimer laser in a single refractive surgery center by a single surgeon. RESULTS: Uncorrected visual acuity (UCVA) improved to 20/20 or more and 20/25 or more in 34 eyes (60.7%) and 56 eyes (100%), respectively, in the wavefront-guided ablation group and in 36 eyes (64.2%) and 54 eyes (96.4%) in the custom-Q ablation group. All eyes had UCVA of 20/40 or better. A total of 54 eyes (96.4%) in the wavefront-guided ablation group and 56 (100%) in the custom-Q ablation group had spherical equivalent (SE) within -/+0.5 D. One eye in each group (2%) lost >or=2 lines of best-corrected visual acuity (BCVA). High order root mean square (RMS) in the wavefront-guided group was 0.3630-/+0.13 mum preoperatively and 0.427-/+0.17 at 3 months (p=0.2). In the custom-Q ablation group it was 0.329-/+0.092 preoperatively and 0.4730-/+0.181 at 3 months after PRK (p=0.08). CONCLUSIONS: Regarding safety and refractive efficacy, custom-Q ablation profiles were clinically equivalent to wavefront-guided profiles in corrections of myopia up to -6.00 D and astigmatism up to 2.50 D.